Difference between revisions of "Reference Electrode Potentials"
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! scope="col" | Reference | ! scope="col" | Reference | ||
|- | |- | ||
| − | ! scope="row" | Hg/Hg2Cl2, KCl (0. | + | ! scope="row" | Hg/Hg2Cl2, KCl (0.1 M) || 0.3337 || 0.0925 || - || 1,3 |
|- | |- | ||
| − | ! scope="row" | Hg/Hg2Cl2, KCl (0. | + | ! scope="row" | Hg/Hg2Cl2, KCl (0.1 M) || 0.336 || 0.092 || Yes || 2 |
|- | |- | ||
! scope="row" | NCE || 0.2801 || 0.0389 || - || 1,3 | ! scope="row" | NCE || 0.2801 || 0.0389 || - || 1,3 | ||
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! scope="row" | NCE || 0.283 || 0.039 || Yes || 2 | ! scope="row" | NCE || 0.283 || 0.039 || Yes || 2 | ||
|- | |- | ||
| − | ! scope="row" | Hg/Hg2Cl2, KCl (3.5M) || 0.250 || 0.006 || Yes || 2 | + | ! scope="row" | Hg/Hg2Cl2, KCl (3. 5M) || 0.250 || 0.006 || Yes || 2 |
|- | |- | ||
! scope="row" | SCE || 0.2412 || 0 || - || 1,3 | ! scope="row" | SCE || 0.2412 || 0 || - || 1,3 | ||
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'''NOTES''' | '''NOTES''' | ||
| − | :SCE, saturated calomel electrode, Hg/ | + | :SCE, saturated calomel electrode, Hg<sub>2</sub >Cl<sub>2</sub> + 2e<sup>–</sup>, KCl (sat'd) |
| − | :SSCE, saturated salt calomel electrode, Hg/ | + | :SSCE, saturated salt calomel electrode, Hg<sub>2</sub >Cl<sub>2</sub> + 2e<sup>–</sup>, NaCl (sat'd) |
| − | :NCE, normal calomel electrode, Hg/ | + | :NCE, normal calomel electrode, Hg<sub>2</sub >Cl<sub>2</sub> + 2e<sup>–</sup>, KCl (1 M) |
:NHE, normal hydrogen electrode | :NHE, normal hydrogen electrode | ||
Revision as of 13:02, 4 August 2014
The calomel electrode is usually constructed from a platinum wire inserted into a mixture of calomel (mercurous chloride, Hg2Cl2) and mercury with an electrolyte solution of KCl or NaCl. The relevant half equation is: Hg2Cl2 + 2e– → 2Hgliq + 2Cl–
| Conditions | vs NHE | vs SCE | LJ | Reference |
|---|---|---|---|---|
| Hg/Hg2Cl2, KCl (0.1 M) | 0.3337 | 0.0925 | - | 1,3 |
| Hg/Hg2Cl2, KCl (0.1 M) | 0.336 | 0.092 | Yes | 2 |
| NCE | 0.2801 | 0.0389 | - | 1,3 |
| NCE | 0.283 | 0.039 | Yes | 2 |
| Hg/Hg2Cl2, KCl (3. 5M) | 0.250 | 0.006 | Yes | 2 |
| SCE | 0.2412 | 0 | - | 1,3 |
| SCE | 0.244 | 0 | Yes | 2 |
| SSCE | 0.2360 | -0.0052 | - | 1 |
NOTES
- SCE, saturated calomel electrode, Hg2Cl2 + 2e–, KCl (sat'd)
- SSCE, saturated salt calomel electrode, Hg2Cl2 + 2e–, NaCl (sat'd)
- NCE, normal calomel electrode, Hg2Cl2 + 2e–, KCl (1 M)
- NHE, normal hydrogen electrode
(1) "Electrochemical Methods: Fundamentals and Applications", AJ Bard & LR Faulkner, John Wiley & Sons, NY (2000). See the table on inside back cover.
(2) "Electrochemistry for Chemists, Second Edition", DT Sawyer, AJ Sobkowiak, J Roberts, Jr., John Wiley & Sons, NY (1995). See Section 5.2.
(3) "Handbook of Analytical Chemistry", L Meites, ed., McGraw Hill, NY (1963). See Sect 5.
